Here are brief descriptions of several file transfer protocols from the
File Download menu help screen of one of the local BBS systems in Dayton.
XMODEM-1k: Like xmodem except that it uses 1024 byte blocks,
sometimes mislabeled as ymodem
Super8k: A fairly new fast protocol
Bimodem: Bimodem was designed to allow transfers in both
directions at once (Upload & Download at the same time). It
also allows chatting while the transfers. *** GOOD ***
**** Bimodem must be used from the download menu ****
Jmodem: Jmodem was designed to maximize the amount of data that
can be transferred in a given time. It sends very long blocks
of data using 16 bit CRC error correction and compressing the
data wherever possible.
Kermit: The Kermit protocol was designed to permit computers
of different types to send files to each other. Almost any
computer using Kermit can be set up to send files to another
computer using Kermit. But it's very, very, very *** SLOW ***.
Lynx: Based on the assumption that a connection between two
sites is capable of full-duplex transmission.
The reason that Lynx makes use of full-duplex operations is
to insure optimum transfer speed.
Lynx can transfer up to 255 files in a single batch.
SEAlink: SEAlink is an advanced version of Xmodem developed by
System Enhancement Associates. It is a sliding window protocol
SEAlink is 15 to 25 percent faster than regular Xmodem. SEAlink
passes a file's name, size, and date when transferring it, and
can be used to send more than one file at a time.
Windowed Xmodem: This is the same as Xmodem except that it
has a longer delay time. This is for use with remote services
that can not tolerate strict timing during Xmodem transfers.
Xmodem: This is the most popular protocol in use today, but it
is slowly being replaced by quicker and more reliable protocols.
Error checking is a checksum or a the sophisticated Cyclic
Redundancy Check. The Xmodem protocol requires a setup of no
parity, 8 data bits, and 1 stop bit. *** SLOW ***
Ymodem (batch): This protocol is a variation on Ymodem, which
allows for multiple files to be sent per transfer. While
transferring files, it keeps the correct name, size, and date,
and may use 128 or 1024 byte block sizes.
Zmodem: This advanced protocol is very *** FAST *** and extremely
RELIABLE, and offers many features. Zmodem can transfer a group
of files in one batch, while keeping the exact file size and
dates. Zmodem can detect and recover from errors quickly, and
can resume an interrupted transfer at a later time (this
feature, called Zmodem Recovery.) Zmodem is also very well
suited for satellite links and packet switched networks.